It is known in the prior art to provide building panels of the foregoing nature. In accordance with one proposal (ROBINSON, U.S. Pat. No. 4,185,437) a frame work of studs is secured to the planar surface of a cementitious slab by applying cementitious overlays at intervals to a flange portion of the studs. The overly increases the thickness of the slab locally, but the studs do not penetrate below the planar surface of the slab. The method is relatively labour intensive, and the quality of the panels may show considerable variance.
In accordance with other proposals, the studs are provided on the flange portion with a downwardly stepped key. The framework of studs is placed onto the slab before set up, so that the key projects below the planar surface of the slab. The key is continuously formed along the length of the stud. Where the mass of cementitious material is relatively limited i.e. in slabs having a thickness of between below about 5 to about 10 cm (2 to 4 inches), the panels can be subject to stress cracking along the line of the key. Where the slabs are even more thin i.e. having a thickness of 2 to 3 cm (3/4 to 11/4 inches), the tensile strength along the line of the key is critically diminished.
Once preformed building panels are installed, they tend to be subject primarily to compressive forces, hence the degree to which the studs are keyed to the slab need not be great. However, during storage, transportation and installation, the studs may be subject to adventitious tensile forces tending to rotate the studs about their longitudinal axis, and also tending to move the studs along their longitudinal axis. In thicker slabs of cementitious material, the keys may be relatively large and deeply embedded and able to withstand the adventitious forces. In the thinner slabs, the keys are necessarily smaller and less deeply embedded, and as a consequence they may break out from the slab under the influence forces.
There is a further problem encountered in preformed building slabs wherein a continuous wire rod or mesh is embedded in the slab. Generally speaking the rod or mesh is attached to the framework of studs, usually by tying with wire, in a labour intensive operation.
It is an object of this invention to provide improvements in preformed building panels comprising a cementitious slab having a framework of studs secured thereto.
It is a further object of this invention to provide building panels of the foregoing nature wherein the cementitious slab may be relatively thin.
It is a still further object of this invention to provide building panels which may be thin and yet which may better withstand certain forces to which they may be subject.
It is yet another object of this invention to provide building panels having a continuous reinforcement embedded therein which is held in place by means formed unitarily with the studs.
It is still another object of this invention to provide studs for use in the construction of building panels.